Photometer.



.No. 640,882. Pat'ented Jan. 9, I900. ,C. DESHLER &. E. J. MBALLISTER.

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No. 640,882. Patented Jan. .9, 1900. c. BESHLER & E. J. McALLlSTER.

PHOTUMETEB.

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PHOTOMETER.

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No. 640,882. Patented Jan. 9, I900.

C. DESHLER &. E. J. MGALLISTER.

PHOTOMETER.

(Application in ed June 16, 1898) (No Model.) 4 Sheetsshed 4.

OD-QEQ TE STATES FATENT CHARLES DESI-ILER, OF NEWV BRUNSWICK, AND EDI/VIN J. MCALLISTER,

OF NEWVARK, NEW JERSEY.

PHOTOMETER.

SPECIFICATION formingpart of Letters Patent No. 640,882, dated January 9, 1900.

Application filed June 16, 1898.

To all Mill/07771 it may concern:

Be it known that we, CHARLES DEsHLER, of New Brunswick, in the county of Middlesex, and EDWIN J. MOALLISTER, of Newark, in the county of Essex, State of New Jersey, citizens of the United States, have invented certain new and useful Improvements in Photometers, of which the following is a specification.

Our invention relates to various new and useful improvements in photometers, which improvements are especially adapted for use with photometers for standardizing or determining the candle power, voltage, or efficiency of incandescent electric lamps.

The principal object of our invention is to produce a portable photometer-that is to say, an instrument of this type which under operative conditions will have sufiicient length to enable the proper accuracy of measurement to be accomplished and at the same time will be capable of being so arranged as to occupy only a relatively small space in transportation. We prefer to so arrange the parts comprising the improved photometer that when they are brought together for transportation they will constitute a compact and essentially rectangular package capable of being contained in a case of moderate size. A photometer which is sufliciently extended to possess the desired accuracy and at the same time can be conveniently transported is a desired instrument"v in this art, since the only photometers now on the market are more or less cumbersome and generally require special tables or stands for their reception.

A further object of our invention is to produce a new standard light which shall be oapable of maintaining an absolutely-constant candle power during extended periods of time. We find that by employing a light-producing device, such as a kerosene-lamp having a normal candle-power, and by operating the same as a standard of very much reduced candle-power a practically uniform and un- Varying standard of light will be secured.

A further object of the invention is to provide means by which without unnecessary complication the light standard may be properly standardized and subsequently be used in the standardization of electric lamps, either Serial No. 683,632. (No model.)

in determining the candle power of such lamps, their voltage, or their efiiciency.

A further object of the invention is to provide minor improvements in the construction and arrangement of the elements as will conduce to the successful and convenient operation thereof, all as will be more fully herein after described and claimed.

In order that our invention may be better understood, we illustrate in the accompanying drawings, which form a part of this speci fication, the preferred form of photometer and the preferred arrangement of the individual elements thereof. The device thus illustrated 1V6 consider to be the preferable embodiment of our invention; but it will be obvious from the following description that various modifications may be made therein v as will be suggested to those skilled in the art to which our invention relates.

In the drawings, Figure l is a perspective of the apparatus ready for operation and viewing the same from the front; Fig. 2, a rear elevation thereof; Fig. 3, a plan view; Fig. 4, a sectional view on the line 44 of Fig. 3, illustrating the joint between the scale-carrying frame and the two standards therefor; Fig. 5, a detail view illustrating the preferred joint between the supplemental section carrying the rheostat and the electric connections and the main frame or base, the view being taken above the line 5 5 of Fig. 3; Fig. 6, asection on the line 6 6 of Fig. 3, illustrating the preferred character of joint between the other supplemental section and the main frame; Fig.7 ,a perspective view illustrating the parts nested together for purposes of transportation; Fig. 8, a cross-sectional View through the same, and Fig. 9 a diagram illustrating the preferred electrical connections.

In all of the above views corresponding parts are represented by the same numerals of reference.

1 represents the main frame or base of the device, and 2 and 3 supplemental frames removably or detachably carried at the ends of the main frame. Each of the secti0ns 2 3 preferably comprises two essentially parallel strips 4: 4; but for convenience in nesting the strips of the section 2 are arranged closer totoo gether than the strips of the section 3. The inner ends of the strips comprising the sections 2 and 3 are received in shallow recesses 5 in the main frame 1, and said sections are removably secured to the main section by means of latches 6, which are of any desired type. Extending up from the base 1 are two tubular standards 7 7. Each of these standards is provided with a vertical slot 8, cut in the upper end thereof, so as to receive a scalecarrying frame 9, said frame comprising a plug 10 at each end, fitting within the standards 7, and two parallel connecting-rods 11 11, which fit within the slots 8. Rods 11 carry a scale 12, which has indicated thereon figures and cross-lines representing the candles of light. Movable longitudinally on the rods 11 11 is a light frame 13, having a handle 14, by which the frame may be shifted, and carrying a spot-box 15 of any desired type.

The spot-box shown consists of a generally open rectangular or cubical frame carrying a central vertical partition having an opening therein, in which opening is placed a sheet of white paper having a central spot of paraflin or other greasy material and two mirrors arranged at an angle to the central partition and by which a reflection of thepaper disk, with the spot, may be obtained by the observer looking into the spot-box from the front of the apparatus. The spot-box carries a pointer 16, which codperates with the scale 12.

The supplemental section 2 carries a rheostat or adjustable resistance 17,which preferably comprises a closely-wound coil of resistance material,such as German-silver wire,the coils being sufficiently separated for purposes of insulation, and over which a contact-ring 18 slides, so as to increase or decrease the number of turns in circuit and to thereby vary the electromotive force of currentaffecting the lamp which is being tested. Section 2 also carries, ata definite distance with respect to the scale 12, a standard 19, on the upper end of which is mounted an incandescentlamp socket for receiving either the standard lamp, by which the light standard will be compared, or any lamp the candle-power,voltage,or efficiency of which is to be tested. The standard 19 comprises, preferably, a tubular support 21, in which is mounted a rod 22, the socket 20 being carried by said rod, and a setscrew 23 being employed to lock the rod 22 at any position in vertical movement. said rod 22 may carry a collar 24., adjustable thereon and secured in place by a set-screw 25, and by means of which the proper position of the standard incandescent lamp having been once determined it will be always maintained by the engagement between the collar 24 and the top of the tube 21.

The supplemental frame 3 carries a standard light-giving device, which is shown as comprising an ordinary petroleum-oil lamp 26, the oil well or fount 27 of which is verti- The cally adjustable on two standards 28 by means of set-screws 29. The lamp 26 is preferably provided with two wicks, which are arranged at right angles to the direction of the scale 12, and the normal candle-power of said lamp is,preferably,much greater than the standard thereof which is to be utilized in the testing of incandescent lamps. In practice we find that by employing an ordinary petroleumlamp having a normal candle-power of about thirty'two candles and by operating the same at a candle-power of about eight candles it will constitute a practically constant and uniform standard light of the latter candle 1 power,which will not vary appreciably during relatively long periods of time and by which a substantially exact standardization of incandescent lamps. may be secured. By ar ranging the lamp 26 so as to be vertically adjustable on the standards 28 and by making the standard 19 so that one section thereof may telescope within the other the standard light and the lamp which is being tested may be always mounted in the desired plane with the spot-box. For purposes of convenience we provide the section 3 with a number of dead or blind sockets 30, in which may be received a series of standard incandescent-lamps 31 of varying candle-powers and voltages. These lamps when thus placed will be below and to either side of the rays of the standard light, so that their presence will not affect inany way the operation of the device.

The supplemental section 2 is provided on either side near the end thereof with an in sulated strip 32 33, made, preferably, of hard rubber or vulcanized fiber. The strip 32 is provided with two binding-posts 34 and 35, to which the main-line wires are carried. The binding-post 35 (see Fig. 9) is connected by a wire 36 to one end of the wire of the resistance 17. -The other binding-post 34 .is connected by a wire 37 to a binding-post 38.

39 is abinding-post on the strip 32, and 40 is a switch which may be employed when desired to connect the binding-posts 38 and 39.

The strip 33 is provided with three binding-posts 41, 42, and 43, a switch at being .placed between the binding-posts 41 and 4.2

when it is desired to connect the same. The binding-post 43 is connected by a flexible wire 45 with the current-collecting ring 18, which works over the resistance 17. The socket 20 is connected by wires 46 between the bindingposts 39 and 41. With the switches 40 and 4 4 closed between the binding posts 38 and 39 and 41 and 42, respectively, current to a lamp in the socket 20 will pass from the binding-post 35, wire 36, resistance 17, collectingring 18, wire 45 to binding-post 43, thence by a wire at? to binding-post 42, switch 44, binding-post 41, socket, lamp, wire 46, bindingpost 39, switch 40, binding-post 38, wire 37 to binding-post 34. The resistance will therefore be included in series with the lamp, and by shifting the collecting-ring 18 with respect to the resistance-wire a greater or less number of turns may be included in this circuit, so as to vary the electromotive force at the lamp.

In order to measure the voltage of the current affecting the lamp, a voltmeter 48 is placed in circuit across the lamp-terminals and preferably between the binding-posts 38 and'42, as shown in Fig. 9. If it is desired to measure the current affecting the lamp, an 7 ammeter 49 may be employed, connecting the binding-posts 41 and 42, and when this ammeter is used the switch 44 will, of course, be opened. By a comparative reading of the voltmeter 48 and ammeter 49 the efficiency of any lamp in the socket 20 will be secured in the usual way; but a direct reading of this efficiency may be secured by employing a watt meter 50, the pressure-terminals of which are connected between the binding-posts 38 and 42 and the lamp-terminals of which are connected between the binding-posts 39 and 41. When this wattmeter is used, therefore, the switch 40 will be opened.

If desired, in the testing of incandescent electric lamps the socket 20 may be rotated in any suitable way as is now common in this art, whereby the entire light-giving capacity of the lamp may influence the spot-box, as will be understood.

In using the apparatus we first properly standardize the lamp 26. This is done in the following way: We first take a standard incandescent electric lamp of a known voltage and candle-power, which is placed in the socket 20. The lamp 26 is then lighted, and the spot-box is shifted on the guide-rods 11 until the pointer 16 indicates the candle-power of the standard electric lamp. Let us assume that the standard electric lamp employed is of sixteen-candle power at a voltage of 101.3 volts. Pointer 16 will therefore be moved to the figure 16 on the scale, and the collecting-ring 18 will be shifted on the resistance until the pressure between the binding-posts 38 and 42 exactly corresponds to 101.3 volts, the known standard of the lamp. The wicks of the lamp 26 are then adjusted until the reflections of -the spots in the two mirrors of the spot-box read absolutely alike, when it will be known with entire certainty that the lamp 26 will be standardized to accord exactly with that of the standard lamp employed. Having thus standardized the lamp 26 and particularly when the standard used is materially below the light-giving power thereof, we have found from actual experience that this standard does not vary perceptibly during long periods of time. It is, however, desirable to check the lamp 26 whenever convenient in order that it may be determined with certainty that the standard is correct.

Having standardized the lamp 26, we proceed with the testing of incandescent lamps in the following manner: The lamp to be tested is placed in the socket 20 and connected into the circuit with the resistance 17 in se- '16 will indicate on the scale the exact candlepower of the lamp being tested. If, however, the lamp is of a known or represented candlepower and it is desired to ascertain if the voltage indicated is sufficient to produce the desired candle-power, the spot-box will be moved until the pointer 16 indicates the represented or known candle-power of the lamp, and the collecting-ring 18 will be shifted relatively to the resistance, so as to vary the. brilliancy of the light until the two spots read alike. The voltmeter will then indicate the pressure of the current affecting the lamp to produce the desired candle-power. By taking comparative readings of both the voltmeter and the ammeter to obtain the pressure on the lamp and the current affecting it a determination of the lamps efficiency will be secured, or if a wattmeter is employed, as described, these two factors will be indicated on the scale thereof and for the same purpose.

When it is desired to nest the parts of the photometer together for purposes of shipment, the sections 2 and 3 are disengaged from the main portion by operating the latches 6. The plugs 10, carrying the guide-rods 11 and spotbox and scale, are then removed from the standards 7. The section 2 is then placed upon the frame 1,with the two strips 4 4 thereof IOO on either side of the standards 7 and with the standard 19 immediately behind and extending parallel with one of said standards 7, the end of the resistance 17 being in contact with the other of said standards. The section 3 is then placed upon the base 1, with the strips 4 4 thereof extending parallel and practically in contact with the strips of the section 2, with the test-lamps 31 on either side of the resistance 17, and with the lamp 26 immediately behind the standard 7 atthat side. The plugs 10 are then inverted and again introduced into the upper ends of the standards 7, with the spot-box hanging downward immediately in front of the resistance 17 and about the sections 2 and 3, which are in contact with the main frame 1. This produces a very com- Having now described our invention, what we claim as new, and desire to secure by Letters Patent, is as follows:

1. As a new article of manufacture, a photometer for testing incandescent electric lamps and comprising a main section carrying a spot-box and scale, and two supplemental sections movable with respect to the main section, one of said supplemental sections carrying-a standard light and the other carrying the electric light to be tested, a rheostat, and connections for a voltmeter and ammeter, substantially as set forth.

2. As a new article of manufacture, a photometer for testing incandescent electric lamps and comprising a main section carrying a spot-box'and. scale, and two supplemental sections movable with respect to the main section, one of said supplemental sections carrying a standard light and the other carrying the electric lightto be tested, a rheostat, and connections for a voltmeter, an ammeter and a wattmeter, substantially as set forth.

3. As a new article of manufacture, a photometer for testing incandescent electric lamps and comprising a main section carrying a spot-box and scale, and two supplemental sections movable with respect to the main'section, one of said supplemental sections carryinga standard light and the other carrying the electric light to be tested, a rlieostat, connections for an ammeter, and a switch for short-circuiting said ammeter, substantially as set forth.

4. As a new article of manufacture, a photometer for testing incandescent electric lamps and comprising a main section, two

vertical standards carried by said main section, a spot-box and scale carried by said standards, two supplemental sections each comprising two parallel strips, one of said sections carrying a standard light and the other carrying the light to be tested, and means for removably securing said supplemental sections to the main section, whereby the supplemental sections may be removed and nested upon the main section with the parallel strips thereof extending on either side of the scale-supporting standards, substantially as set forth.

5. As a new article of manufacture, a photometer for testing incandescent electric lamps and comprising a main section, two vertical standards carried by said main section, a spot-box and scale carried by said standards and capable of being inverted with respect to the same, two supplemental sections each comprising two parallel strips, one of said sections carrying a standard light and the other carrying the light to be tested, and means for removably securing said supplemental sections to the main section, whereby the supplemental sections may be removed and nested upon the main section with the parallel strips thereof extending on either side of the scale-supporting standards, substantially as set forth.

This specification signed and witnessed this 19th day of May, 1898.

CHARLES DESHLER. EDWIN J. MCALLISTER.

Witnesses:

FRANK L. DYEB, Jno. R. TAYLOR. 

